Effect of EM inoculum on the microbiological state of substrate designed for pelargonium (Pelargonium × hortorum)

Summary.

The objective of the presented studies was the determination of the developmental dynamics of selected microorganism groups and the activity of dehydrogenases in the substrate with an addition of microbiological EM inoculation designed to promote growth and flowering of pelargonium (Pelargonium × hortorum) ‘Trend Lavender’. The material used for the studies consisted of peat substrate with pH 5.5-6.0, as well as of peat substrate with an addition of loess-like loam. Both substrates were enriched with a delayed action multi-component fertilizer Osmocote 5-6 M in the amount of 3 g·dm-3. Bed pelargonium transplants of ‘Trend Lavender’ cultivar were planted into flower pots of 12 cm diameter and was inoculated with different doses of EM (1:10, 1:50, 1:100). Samples of substrate, in which the plants were grown, were taken in three developmental phases (transplants plantation, vegetative growth, flowering). The studies included the following range: developmental dynamics of the total number of bacteria, actinomycetes and mould fungi development using the plate method of Koch. The level of dehydrogenases was determined in the experiment by the spectrophotometric method. On the basis of the obtained results, it was found that the introduction of inoculum in the form of Effective Microorganisms into the peat substrate contributed to the impediment of the development of the moulds and to the growth of the bacteria and actinomycetes number. The presented studies permitted to conclude that foliar application of EM-inoculation in the 1:10 concentration impeded the development of the studied groups of microorganisms. Furthermore, it was found that the greatest number of moulds occurred in the phase of transplant plantation. On the other hand, the greatest number of bacteria, actinomycetes and dehydrogenases activity occurred in the phase of flowering. Moreover, application of EM solution did not have any effect on height of plants, number of leaves and greening leaf index, as well as on length of inflorescences. However, positive effect was observed in the case of number of pitches and flowers, as well as on earliness of flowering. Application of EM solution caused one week earlier flowering in comparison to control plants. Investigation revealed decrease of chlorophyll a + b content in leaves of plants cultivated at substrate of peat with clay treated with various EM concentrations, while increase of chlorophyll content was noticed in plants cultivated at substrate peat without clay addition.